Rotary trimmer with switchable blades

ABSTRACT

The rotary trimmer with switchable blades of the present invention comprises a base with end retainers moveably supporting a rail, and a cutting assembly disposed on the rail. The cutting assembly includes a switching mechanism to switch between different blades by turning a switch knob accessible outside the housing containing the switching mechanism and the blades. The different blades can have different cutting edges such as a straight, patterned, scalloped, pinking, wave, perforating, or zig-zag edge. Turning the switch knob rotates the desired blade into radial position and locates the desired blade axially over a cutting strip. A clutch engages the switching mechanism during cutting to prevent rotation or axial movement of the switching mechanism.

TECHNICAL FIELD

The technical field of this disclosure is cutting and trimming devices,particularly, a rotary trimmer with switchable blades.

BACKGROUND OF THE INVENTION

Rotary trimmers are used to cut paper and other sheet materials, such ascardboard, leather, fabric, plastics, and similar materials. Typically,a sharpened circular blade is mounted in a housing and heldperpendicular to a cutting board, and the blade rolled across thecutting board to cut the various materials.

Different types of blades can be used for different applications. Whilea straight cut may be desirable for simply trimming the edge of a sheetof paper, different cuts may be desirable for other applications. Adecorative cut with a scalloped or zig-zag edge may be desirable forcraft projects, such as scrapbooks. A zig-zag pinking edge may also bedesirable when cutting fabric to avoid fraying. A perforated cut can beused to make tear away forms or for decoration. Although many patternsare useful or desirable, each requires a different blade to make thecut.

Current rotary trimmers require that one blade be manually replaced withanother blade when a different shape cut is desired. The user must opena housing, dismount the installed blade, mount the new blade, replacethe housing, and store the old blade. The user must handle the exposedblade and risk being cut. This risk prevents children from being able tochange the cutter and the cutter pattern. Along with the inconvenienceof having to physically switch out the blades, there is the need toprovide storage for the blades and the risk that the blades may be lost.U.S. Pat. No. 5,322,001 to Boda, issued Jun. 21, 1994, discloses acutting board assembly for cutting and/or trimming paper sheets using asingle rotary blade and including a few interchangeable blades and arecess in the cutting board for storing the various cutting blades.

It would be desirable to have a rotary trimmer with switchable bladesthat would overcome the above disadvantages.

SUMMARY OF THE INVENTION

One aspect of the present invention provides a rotary trimmer withswitchable blades that provides various cutting blades without the needto manually change out the blades.

Another aspect of the present invention provides a rotary trimmer withswitchable blades that avoids handling the blade.

Another aspect of the present invention provides a rotary trimmer withswitchable blades that can be used by anyone.

Another aspect of the present invention provides a rotary trimmer withswitchable blades that provides internal storage for blades.

The foregoing and other features and advantages of the invention willbecome further apparent from the following detailed description of thepresently preferred embodiments, read in conjunction with theaccompanying drawings. The detailed description and drawings are merelyillustrative of the invention, rather than limiting the scope of theinvention being defined by the appended claims and equivalents thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a first embodiment of a rotarytrimmer with switchable blades made in accordance with the presentinvention.

FIGS. 2 & 3 show a perspective view and exploded view, respectively, ofthe switching mechanism of a rotary trimmer with switchable blades ofFIG. 1 made in accordance with the present invention.

FIG. 4 shows a detail perspective view of the clutch and pusher of arotary trimmer with switchable blades of FIG. 1 made in accordance withthe present invention.

FIGS. 5 & 6 show a detail view and exploded view, respectively, of thecutters of a rotary trimmer with switchable blades of FIG. 1 made inaccordance with the present invention.

FIGS. 7 a-9 b show detailed views of exemplary embodiments of cutters ofa rotary trimmer with switchable blades made in accordance with thepresent invention.

FIG. 10 shows a perspective view of a second embodiment of a rotarytrimmer with switchable blades made in accordance with the presentinvention.

FIG. 11 shows an exploded perspective view of the rotary trimmer withswitchable blades of FIG. 10 made in accordance with the presentinvention.

FIGS. 12 & 13 show a detail view and exploded view, respectively, of thecutting assembly of a rotary trimmer with switchable blades of FIG. 10made in accordance with the present invention.

DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT

The rotary trimmer with switchable blades of the present inventioncomprises a base with end retainers moveably supporting a rail, and acutting assembly disposed on the rail. The cutting assembly includes aswitching mechanism to switch between different blades by turning aswitch knob accessible outside the housing containing the switchingmechanism and the blades. The different blades can have differentcutting edges such as a straight, patterned, scalloped, pinking, wave,perforating, or zig-zag edge. Turning the switch knob rotates thedesired blade into radial position and locates the desired blade axiallyover a cutting strip. A clutch engages the switching mechanism duringcutting to prevent rotation or axial movement of the switchingmechanism.

FIG. 1 shows a perspective view of a rotary trimmer with switchableblades made in accordance with the present invention. The rotary trimmer30 comprises a base 32, end retainers 34 moveably supporting a rail 36,and a cutting assembly 50 disposed on the rail 36. A ruler 38 isdisposed on the base 32. A self-healing strip 40, recessed in the base32, receives the blade during cutting. The cutting assembly 50 comprisesa lower housing 52, an upper housing 54, a push knob 56, and a switchknob 58. The switch knob 58 is connected to the switching mechanism (notshown) within the housing and controls the blade selection. Although theswitch knob 58 is presented as an example of the means for the user toselect the desired blade, those skilled in the art will appreciate thatother mechanisms, such as a lever, handle, switch, bar, button, or thelike, can be used without departing from the spirit of the invention.

To cut a sheet with the rotary trimmer 30, the desired blade can beselected by turning the switch knob 58 to the desired blade indication.The sheet (not shown) to be cut is positioned on the base 32 below theruler 38 and rail 36. The cutting assembly 50 is positioned where thecut is to start, the push knob 56 depressed to lock the blade positionand to lock the sheet in position by pressing the ruler 38 toward thebase 32. The cutting assembly 50 can then be slid along the rail 36 tomake the cut and the push knob 56 released at the end of the cut.

FIGS. 2 & 3 show a perspective view and exploded view, respectively, ofthe switching mechanism of a rotary trimmer with switchable blades madein accordance with the present invention. The switching mechanism 60 istypically housed within the upper housing 54 and lower housing 52 of thecutting assembly. A shaft 62, of a cruciform profile, supports andoperably connects the components of the switching mechanism 60. Theswitch knob 58 is fixedly connected to the shaft 62 and the cam driver70. In an alternate embodiment, the switch knob 58 and the cam driver 70can be a single piece.

A cam 80, blades 90, a washer 98, a pusher 100, and a spring 110 areslidably supported on the shaft 62. The end of the spring 110 away fromthe pusher 100 contacts a stationary bearing surface in the lowerhousing 52, so that the spring 110 urges the cam 80, the blades 90, thewasher 98, and the pusher 100 toward the switch knob 58.

The cam driver 70 has an extended boss 72, which moves the cam 80axially through the force of the extended boss 72 along a sloped surface82 of the cam 80. In turn, the cam 80 moves the desired blade 90 axiallyinto cutting position. The stack of blades 90 and the pusher 100 areurged toward the cam 80 by the spring 110. The cam 80 can includesemi-spherical pits 86 in the sloped surface 82 to act as positive stopswhen the switch knob 58 is at a cutting position for one of the blades90. As the cam 80 moves the desired blade into axial position, therotation of the shaft 62 moves the desired blade into radial position.

The shaft 62 passes through a circular opening in the cam 80, so the cam80 does not rotate when the shaft 62 is turned. Cam rib 84 is slidablydisposed in a slot in the lower housing 52 to prevent the cam 80 fromrotating while allowing the cam 80 to slide axially on the shaft. Theshaft 62 passes through cruciform openings 96 in the blades 90 andpusher 100, so the blades 90 and pusher 100 rotate when the shaft 62 isturned. The cruciform opening 96 can be on the axis for the pusher 100and off the axis (eccentric) for the blades 90. In one embodiment, thepusher 100 and the spring 110 can be made as a single piece. The pusher100 has pusher ribs 104 that are used with the clutch 130 to keep theswitching mechanism 60 from rotating or shifting axially during cutting.

The switching mechanism 60 is supported at the switch knob 58 insemicircular cutouts in the upper and lower housings where the switchknob 58 passes into the housing and at the rail end by bearing surfacesin the lower housing 52. A traveling spring 112 can be mounted betweenthe rail 36 and the lower housing, and operably connected to the lowerhousing, to urge the lower housing against the upper portion of therail. In one embodiment, the traveling spring 112 can be a leaf springmade of plastic, although those skilled in the art will appreciate thatmany shapes and materials are suitable for the intended use.

A clutch mechanism 120 comprises the push knob 56, a clutch 130, and apad 140. A push knob stem 57 passes through an opening in the upperhousing and engages the clutch 130. The pad 140 slidably supports theclutch 130 on the rail 36. The pad 140 can have a low coefficient offriction with the rail 36 to allow the cutting assembly to easily slidealong the rail during cutting. The clutch 130 engages the pusher 100when the push knob 56 is depressed, to prevent rotation or axialmovement of the switching mechanism 60 during cutting.

To use the rotary trimmer, the user turns the switch knob 58 so that theindicia on the switch knob 58 corresponding to the desired cut design orblade lines up with a mark on the housing. The switch knob 58 rotatesthe cam driver 70, moving the extended boss 72 along the sloped surface82 of the cam 80 until the extended boss 72 stops in the pit 86, and theselected blade 90 is in the final axial location over the self-healingstrip in the base. As the axial movement occurs, the rotation of theswitch knob 58 rotates the shaft 62 together with the blades 90,bringing the selected blade 90 into the final radial position at a slotin the lower housing. With the selected blade in position, the userdepresses the push knob 56, which moves the clutch 130 to lock thepusher 100 in position. Continued pressure on the push knob 56 moves therail downward so that the sheet to be cut is held between the ruler andthe base and the selected blade engages the sheet. The user slides thecutting assembly along the rail to make the cut as the blade's cutterrotates about its hub, releases the push knob 56 to release the cutsheet, and finishes the cutting operation.

FIG. 4 shows a detail perspective view of the clutch and pusher of arotary trimmer with switchable blades made in accordance with thepresent invention. When the push knob is depressed, the clutch 130positively engages the pusher 100 to prevent rotation and axialmovement. When the push knob is in the up position, the clutch 130 andpusher 100 are disengaged and the switching mechanism, including thepusher 100, is free to rotate. The engaging portion 132 of the clutch130 mates with the flats of the pusher ribs 104 to prevent rotation ofthe shaft, which passes through a cruciform central opening 102 of thepusher 100. The engaging portion 132 of the clutch 130 can also projectinto the space between the pusher ribs 104 to axially restrain thepusher 100. When the push knob is in the up position, the clutch 130 isfree of the pusher 100, so that the pusher 100 can rotate freely withthe shaft 62, or move axially along the shaft. Those skilled in the artwill appreciate that a number of mechanisms can accomplish the goal ofpreventing rotation and axial movement. In one embodiment, the clutchand pusher could be omitted and the rotation of the switch knobrestrained to lock the shaft. In another embodiment, the pusher could beomitted and the clutch could engage the shaft directly. In yet anotherembodiment, the clutch could have a pin that passes through the pusherand/or shaft to lock the position.

FIGS. 5 & 6 show a detailed view and exploded view, respectively, of thecutters of a rotary trimmer with switchable blades made in accordancewith the present invention. The blade 90 comprises a circular cutter 92disposed about a blade hub 94, the blade hub 94 having the cruciformopening 96, eccentrically positioned for receiving the shaft 62. Theblade 90 can have a straight cutting edge as shown, or can have apatterned edge, including but not limited to, a scalloped, pinking,wave, perforating, or zig-zag edge. The blade 90 can cut a sheetcompletely with a straight cut or a decorative cut, or can leave thesheet intact and cut a perforation or series of decorative holes ordesigns. The cutter 92 is rotatable about the blade hub 94, so that thecutter 92 can rotate about the blade hub 94 during cutting. In oneembodiment, the blade hub 94 can be retained in the cutter 92. Inanother embodiment, the blade hub 94 can fit loosely in the cutter 92and the fit maintained by the force of the pusher on the stack ofblades.

As shown in FIG. 5, the blades 90 can be mounted on the shaft 62 witheach hub rotated by ninety degrees, so that the maximum distance betweenthe shaft 62 and the blade edge points a different direction for eachblade. Thus, rotating the shaft by ninety degrees moves a differentblade into cutting position. It will be appreciated by those skilled inthe art that the number of blades can be more or fewer than the fourblades shown as an example, as required to suit a particularapplication.

FIGS. 7 a-9 b show detailed views of exemplary embodiments of cutters ofa rotary trimmer with switchable blades made in accordance with thepresent invention. FIGS. 7 a & 7 b illustrate a blade for making ascallop-like cut. FIGS. 8 a & 8 b illustrate a blade for making apinking cut. FIG. 9 a illustrates a simple cutting edge for straightline cutting and FIG. 9 b illustrates a blade for making a perforationcut.

FIGS. 10 to 13 illustrate a second embodiment of a rotary trimmer withswitchable blades made in accordance with the present invention. Thisembodiment may also use the blades illustrated in FIGS. 7 a to 9 b.

FIGS. 10 & 11 shows a perspective view and an exploded view,respectively, of a second embodiment of a rotary trimmer with switchableblades made in accordance with the present invention. The rotary trimmer200 comprises a base 232, end retainers 234 moveably supporting a rail236, and a cutting assembly 250 disposed on the rail 236. The rail 236is slidably secured in rail openings 239. A self-healing strip 240recessed in the base 232 receives the blade during cutting. The endretainers 234 may include rail retainers 224. Rail retainers 224 can beopened to allow the rail to be removed so that the cutting assembly 250may be removed for replacement of the assembly 250 or the blades. Aruler 238 is disposed on the base 232 and may be secured in ruler slots239. Finger recesses 241 are formed as semispherical pits in the surfaceof the base 232 for the easy removal of the self-healing strip 241.

The cutting assembly 250 comprises a lower housing 251 having an upperportion 252 and lower portion 253, an upper housing 254, and a push knobportion 256. The lower housing 251 is connected to the switchingmechanism (not shown) within the housing and controls the bladeselection. The rotation of the lower housing 251 changes the selectionof the blade as the blades are rotated about a central axis of thecutting assembly 250.

The rotary trimmer 200 further comprises a spare blade compartment forstoring spare cutting blades. The spare blade compartment includes acover 222, and a plurality of blade compartments 226. The cover 222 maybe slidably attached to the trimmer 200 and may be flush with thesurface of the base so as not to interfere with the placement of thematerial to be cut.

FIGS. 12 & 13 show a detail view and exploded view, respectively, of thecutting assembly 250 of a rotary trimmer 200 with switchable blades ofFIG. 10 made in accordance with the present invention. The cuttingassembly 250 includes the upper housing 254, the lower housing 251, anindexing plate 264, and cutting blade assemblies 280.

The cutting assembly 250 slides along the rail 236 during operation. Theupper housing 254 includes a pair of rail openings 255 that receive therail 236.

The upper housing includes the push knob portion 256, a threadedcentering pin 257, and a spring 260 placed around the centering pin 257.The spring 260 is a compression spring having one end containing aninside surface of the housing 254 and a second end contacting a topsurface of the indexing plate 264. The housing 254 further includes acutting blade activation pin 262. The pin 262 is located on, and extendsfrom, the bottom surface of the knob portion 256 of the housing 254. Thepin 262 may be formed integrally with housing 256, or may be formedseparately and then securely attached by means well known in the art.

The indexing plate 264 includes an activation pin opening 266 throughwhich the pin 262 reciprocatingly moves in order to activate the cuttingblade. The indexing plate 264 further includes an indexing pin 268 forindexing the cutting assembly when the lower housing is rotated whenchanging the current blade to a different blade contained within theassembly. The indexing plate 264 also includes a central opening throughwhich the centering pin 257 passes for alignment of the variouscomponents of the assembly 250.

The lower housing 251 includes an upper portion 252 and a lower portion253. The upper portion 252 is placed adjacent the indexing plate 264.The upper portion 252 of the housing 251 includes a central openingthrough which the pin 257 passes. The upper portion 252 also includes aplurality of openings, each opening receives a blade-actuating device276. The upper portion 252 further includes a plurality of semi-circularpits 272 that receive an end portion of the indexing pin 268.

The blade-actuating device 276 includes a top surface for contacting thepin 262. In one embodiment, the top surface includes a raised portion274 that contacts the end portion of pin 262. The shape of the raisedportion 274 corresponds with the shape of the pin 262. In otherembodiments, the blade-actuating device 276 does not include a raisedportion 274 but includes a longer pin 262 for contacting and engagingthe top surface of the blade-actuating device 276. The blade-actuatingdevice 276, on the underside surface, further includes two spaced apartarches 275. Arches 275 each include a contact surface 277 for contactinga blade assembly 280.

The blade assembly 280 includes a cutting blade 282 and a hub 283 thatextends on either side of the blade and forms a surface for contactingthe blade-actuating device 276.

The shape of the arch 275 corresponds to the shape of the hub 283 of theblade assembly 280. The dual arch of the blade-actuating device 276 issuch that when the surface 277 contacts the hub surface on either sideof the blade, the blade is still free to rotate during the materialcutting process. The blade-actuating device 276 and the hub 283 may beexecuted from dissimilar synthetic materials in order to reducefriction.

The lower housing portion 253 defines a plurality of pocket openings292, each for receiving a single blade assembly. Each of the pockets 292also receives a pair of leaf springs 290. The leaf springs 290 arepositioned within the pocket openings 292 such that, during operation ofthe cutting assembly, the hub 283 presses down on the leaf spring. Uponrelease of the knob, the leaf springs moves the blade assembly from acutting position into a resting position.

The lower housing portion 253 further includes a plurality of openingson the underside of the housing through which an attachment device isinserted in order to secure the upper portion 252 of the lower housingto the lower portion 253 of the lower housing. These attachment devicesmay take the form of screws 248. Lower housing portion 253 also includesa centering cylinder 247 for receiving the centering pin 257. Anattachment device 294 is used to secure the upper housing 254 to thelower housing 251 via the centering pin 257. Those with skill in the artwill recognize that there are many other ways of removable securing theupper housing to the lower housing.

In operation, the user selects the appropriate blade by rotating thelower housing 251. Once selected, the user presses down on the knob 256causing the pin 262 to move through the opening 266 to contact theblade-actuating device 276. The blade-actuating device 276 will thenmove to contact the hub 283 of the blade assembly 280. Further downwardpressure on the knob 256 causes the blade assembly to move from aresting position to a cutting position, the blade moving through anopening in the lower portion of the lower housing 251 and contacting thematerial to be cut. Sliding the assembly 250 over the rail 236 will cutthe intended material. Release of the pressure on the knob will causethe leaf springs to push against the blade assembly to move the bladefrom a cutting position into the resting position.

It is important to note that FIGS. 1-13 illustrate specific applicationsand embodiments of the present invention, and is not intended to limitthe scope of the present disclosure or claims to that which is presentedtherein. For example, more or less than four blades could be used. Uponreading the specification and reviewing the drawings hereof, it willbecome immediately obvious to those skilled in the art that myriad otherembodiments of the present invention are possible, and that suchembodiments are contemplated and fall within the scope of the presentlyclaimed invention.

While the embodiments of the invention disclosed herein are presentlyconsidered to be preferred, various changes and modifications can bemade without departing from the spirit and scope of the invention. Thescope of the invention is indicated in the appended claims, and allchanges that come within the meaning and range of equivalents areintended to be embraced therein.

1. A rotary trimmer comprising: a base; end retainers, the end retainersattached to the base; a rail, the rail moveably supported by the endretainers; and a cutting assembly, the cutting assembly havingswitchable blades and means for switching the switchable blades.
 2. Therotary trimmer of claim 1 further comprising a self-healing stripdisposed in the base for receiving the switchable blade while cutting.3. A switching mechanism for a rotary trimmer comprising: a shaft; a camdriver, the cam driver being fixed on the shaft and having an extendedboss; a cam, the cam being slidably supported on the shaft and having asloped surface, the sloped surface operably connectable to the extendedboss; at least one blade, the blade being slidably supported on theshaft through an eccentric opening; and a spring, the spring beingslidably supported on the shaft and urging the blade towards the cam. 4.The switching mechanism of claim 3 wherein the switching mechanism has aplurality of blades.
 5. The switching mechanism of claim 3 wherein theshaft is cruciform and the eccentric opening is cruciform.
 6. Theswitching mechanism of claim 5 wherein the switching mechanism has fourblades.
 7. The switching mechanism of claim 3 wherein the blade isselected from the group consisting of a straight edged blade, patternededged blade, scalloped edged blade, pinking edged blade, wave edgedblade, perforating edged blade, and zig-zag edged blade.
 8. Theswitching mechanism of claim 3 further comprising: a pusher, the pusherbeing slidably supported on the shaft; and a clutch, the clutch beingmateably connectable to the pusher.
 9. The switching mechanism of claim8 wherein the pusher has pusher ribs and the clutch has an engagingportion mateable with the pusher ribs.
 10. The switching mechanism ofclaim 3 wherein the blade comprises a blade hub and a cutter rotatablydisposed on the blade hub.
 11. The switching mechanism of claim 3wherein the sloped surface further comprises pits for receiving theextended boss.
 12. A switching mechanism for a rotary trimmercomprising: a shaft; at least one blade, the blade being slidablysupported on the shaft; means for rotating the shaft; and means formoving the blade into cutting position responsive to the shaft rotatingmeans.
 13. The switching mechanism of claim 12 wherein the switchingmechanism further comprises a plurality of blades.
 14. The switchingmechanism of claim 12 wherein the means for moving the blade furthercomprises means for moving the blade axially and means for moving theblade eccentrically.
 15. The switching mechanism of claim 13 wherein themeans for moving the blade further comprises means for urging the bladetoward the means for moving the blade axially.
 16. The switchingmechanism of claim 12 further comprising means for locking the blade inthe cutting position.
 17. The switching mechanism of claim 16 whereinthe means for locking the blade in the cutting position furthercomprises means for locking the blade axially and means for locking theshaft radially.
 18. The switching mechanism of claim 12 wherein theblade further comprises means for cutting and means for supporting thecutting means on the shaft.
 19. The switching mechanism of claim 12wherein the blade further comprises means for perforating and means forsupporting the perforating means on the shaft.
 20. A switching mechanismfor a rotary trimmer comprising: a shaft, the shaft being cruciform; aswitch knob fixed on the shaft; a cam driver, the cam driver fixed inrelation to the shaft and having an extended boss; a cam, the camslidably supported on the shaft and having a sloped surface, the slopedsurface contacting the extended boss; a plurality of blades, theplurality of blades each having a cruciform eccentric opening, theplurality of blades being slidably supported on the shaft through thecruciform eccentric openings; a pusher, the pusher having a cruciformcentral opening, being slidably supported on the shaft through thecruciform central opening, and having a plurality of pusher ribs; aspring, the spring slidably supported on the shaft, the spring urgingthe pusher and plurality of blades toward the cam; a push knob; and aclutch responsive to the push knob, the clutch having an engagingportion mateable with the plurality of pusher ribs.
 21. A rotarytrimmer, comprising: a base; a rail mounted to said base; a cuttingassembly slidably mounted on said rail; and, a plurality of bladesmounted in said cutting assembly, wherein said cutting assembly isrotatable to selectively position a desired one of said blades in anoperative position relative to said base.
 22. The rotary trimmer ofclaim 21, wherein said cutting assembly comprises a knob rotatable tocontrollably position a selected one of said blades in an operativeposition.
 23. The rotary trimmer of claim 22, wherein said knob includesindicia indicating a corresponding selected blade.
 24. The rotarytrimmer of claim 23, wherein said cutting assembly defines positivestops engagable with said knob to indicate when a blade is in theoperative position.
 25. The rotary trimmer of claim 22, wherein saidcutting assembly is rotatable to at least four positions to selectivelyposition said blades.
 26. The rotary trimmer of claim 25, wherein saidplurality of blades comprises at least three circular cutting blades.27. The rotary trimmer of claim 26, wherein said circular cutting bladesinclude at least a straight edge blade, a scalloped edge blade, and aperforating blade.
 28. The rotary trimmer of claim 27, wherein saidcutting assembly is downwardly movable towards said base to engage theselected blade with one or more sheets of paper arranged on said base.29. The rotary trimmer of claim 28, wherein said cutting assemblycomprises a clutch operative when said cutting assembly is downwardlymoved, wherein said clutch prevents the selected blade from moving fromthe operative position.
 30. The rotary trimmer of claim 22, wherein saidknob controls a rotatable shaft and wherein said blades are radiallypositioned around said shaft such that rotation of said shaftcontrollably positions a selected one of said blades in the operativeposition.
 31. The rotary trimmer of claim 30, wherein said cuttingassembly comprises a spring outwardly biasing said knob from saidcutting assembly.
 32. The rotary trimmer of claim 31, wherein saidcutting assembly comprises a pusher disposed between said spring andsaid blades.
 33. A rotary trimmer comprising: a base; a rail moveablymounted to said base; a cutting assembly slidably mounted on said rail;wherein said cutting assembly is rotatable to at least four positions toposition a selected one of a plurality of blades in an operativeposition relative to said base; said cutting assembly comprising: ahousing; at least three circular cutting blades mounted in said housing;a rotatable shaft, wherein said at least three circular cutting bladesare radially positioned around said shaft such that rotation of saidshaft controllably positions a selected one of said blades in saidoperative position; and, a knob operable to controllably rotate saidshaft.